Fix oscillating DREAMING states

Remove the delay, and use a debounce instead, which
will prevent oscillating dream values from emitting.

Fixes: 338634549
Test: atest KeyguardInteractorTest
Test: manual - follow repro steps in bug and test all
DREAMING cases
Flag: None

Change-Id: I9188d9f36c364926ce3b77f2b5eba9f3093e46df